1 files changed, 366 insertions, 0 deletions

diff --git a/libblkid/topology.c b/libblkid/topology.c
new file mode 100644
index 000000000..9d4e7bdf1
--- /dev/null
+++ b/libblkid/topology.c
@@ -0,0 +1,366 @@
+/*
+ * topology - gathers information about device topology
+ *
+ * Copyright 2009 Red Hat, Inc.  All rights reserved.
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stddef.h>
+
+#include "topology.h"
+
+/**
+ * SECTION:topology
+ * @title: Topology information
+ * @short_description: block device topology information.
+ *
+ * The topology chain provides details about Linux block devices, for more
+ * information see:
+ *
+ *      Linux kernel Documentation/ABI/testing/sysfs-block
+ *
+ * NAME=value (tags) interface is enabled by blkid_probe_enable_topology(),
+ * and provides:
+ *
+ * @LOGICAL_SECTOR_SIZE: this is the smallest unit the storage device can
+ *                       address. It is typically 512 bytes.
+ *
+ * @PHYSICAL_SECTOR_SIZE: this is the smallest unit a physical storage device
+ *                        can write atomically. It is usually the same as the
+ *                        logical sector size but may be bigger.
+ *
+ * @MINIMUM_IO_SIZE: minimum size which is the device's preferred unit of I/O.
+ *                   For RAID arrays it is often the stripe chunk size.
+ *
+ * @OPTIMAL_IO_SIZE: usually the stripe width for RAID or zero. For RAID arrays
+ *                   it is usually the stripe width or the internal track size.
+ *
+ * @ALIGNMENT_OFFSET: indicates how many bytes the beginning of the device is
+ *                    offset from the disk's natural alignment.
+ *
+ * The NAME=value tags are not defined when the corresponding topology value
+ * is zero. The MINIMUM_IO_SIZE should be always defined if kernel provides
+ * topology information.
+ *
+ * Binary interface:
+ *
+ * blkid_probe_get_topology()
+ *
+ * blkid_topology_get_'VALUENAME'()
+ */
+static int topology_probe(blkid_probe pr, struct blkid_chain *chn);
+static void topology_free(blkid_probe pr, void *data);
+static int topology_is_complete(blkid_probe pr);
+static int topology_set_logical_sector_size(blkid_probe pr);
+
+/*
+ * Binary interface
+ */
+struct blkid_struct_topology {
+	unsigned long	alignment_offset;
+	unsigned long	minimum_io_size;
+	unsigned long	optimal_io_size;
+	unsigned long	logical_sector_size;
+	unsigned long	physical_sector_size;
+};
+
+/*
+ * Topology chain probing functions
+ */
+static const struct blkid_idinfo *idinfos[] =
+{
+#ifdef __linux__
+	&ioctl_tp_idinfo,
+	&sysfs_tp_idinfo,
+	&md_tp_idinfo,
+	&dm_tp_idinfo,
+	&lvm_tp_idinfo,
+	&evms_tp_idinfo
+#endif
+};
+
+
+/*
+ * Driver definition
+ */
+const struct blkid_chaindrv topology_drv = {
+	.id           = BLKID_CHAIN_TOPLGY,
+	.name         = "topology",
+	.dflt_enabled = FALSE,
+	.idinfos      = idinfos,
+	.nidinfos     = ARRAY_SIZE(idinfos),
+	.probe        = topology_probe,
+	.safeprobe    = topology_probe,
+	.free_data    = topology_free
+};
+
+/**
+ * blkid_probe_enable_topology:
+ * @pr: probe
+ * @enable: TRUE/FALSE
+ *
+ * Enables/disables the topology probing for non-binary interface.
+ *
+ * Returns: 0 on success, or -1 in case of error.
+ */
+int blkid_probe_enable_topology(blkid_probe pr, int enable)
+{
+	if (!pr)
+		return -1;
+	pr->chains[BLKID_CHAIN_TOPLGY].enabled = enable;
+	return 0;
+}
+
+/**
+ * blkid_probe_get_topology:
+ * @pr: probe
+ *
+ * This is a binary interface for topology values. See also blkid_topology_*
+ * functions.
+ *
+ * This function is independent on blkid_do_[safe,full]probe() and
+ * blkid_probe_enable_topology() calls.
+ *
+ * WARNING: the returned object will be overwritten by the next
+ *          blkid_probe_get_topology() call for the same @pr. If you want to
+ *          use more blkid_topopogy objects in the same time you have to create
+ *          more blkid_probe handlers (see blkid_new_probe()).
+ *
+ * Returns: blkid_topopogy, or NULL in case of error.
+ */
+blkid_topology blkid_probe_get_topology(blkid_probe pr)
+{
+	return (blkid_topology) blkid_probe_get_binary_data(pr,
+			&pr->chains[BLKID_CHAIN_TOPLGY]);
+}
+
+/*
+ * The blkid_do_probe() backend.
+ */
+static int topology_probe(blkid_probe pr, struct blkid_chain *chn)
+{
+	size_t i;
+
+	if (!pr || chn->idx < -1)
+		return -1;
+
+	if (!S_ISBLK(pr->mode))
+		return -1;	/* nothing, works with block devices only */
+
+	if (chn->binary) {
+		DBG(DEBUG_LOWPROBE, printf("initialize topology binary data\n"));
+
+		if (chn->data)
+			/* reset binary data */
+			memset(chn->data, 0,
+					sizeof(struct blkid_struct_topology));
+		else {
+			chn->data = calloc(1,
+					sizeof(struct blkid_struct_topology));
+			if (!chn->data)
+				return -1;
+		}
+	}
+
+	blkid_probe_chain_reset_vals(pr, chn);
+
+	DBG(DEBUG_LOWPROBE,
+		printf("--> starting probing loop [TOPOLOGY idx=%d]\n",
+		chn->idx));
+
+	i = chn->idx < 0 ? 0 : chn->idx + 1U;
+
+	for ( ; i < ARRAY_SIZE(idinfos); i++) {
+		const struct blkid_idinfo *id = idinfos[i];
+
+		chn->idx = i;
+
+		if (id->probefunc) {
+			DBG(DEBUG_LOWPROBE, printf(
+				"%s: call probefunc()\n", id->name));
+			if (id->probefunc(pr, NULL) != 0)
+				continue;
+		}
+
+		if (!topology_is_complete(pr))
+			continue;
+
+		/* generic for all probing drivers */
+		topology_set_logical_sector_size(pr);
+
+		DBG(DEBUG_LOWPROBE,
+			printf("<-- leaving probing loop (type=%s) [TOPOLOGY idx=%d]\n",
+			id->name, chn->idx));
+		return 0;
+	}
+
+	DBG(DEBUG_LOWPROBE,
+		printf("<-- leaving probing loop (failed) [TOPOLOGY idx=%d]\n",
+		chn->idx));
+	return 1;
+}
+
+static void topology_free(blkid_probe pr __attribute__((__unused__)),
+			  void *data)
+{
+	free(data);
+}
+
+static int topology_set_value(blkid_probe pr, const char *name,
+				size_t structoff, unsigned long data)
+{
+	struct blkid_chain *chn = blkid_probe_get_chain(pr);
+
+	if (!chn)
+		return -1;
+	if (!data)
+		return 0;	/* ignore zeros */
+
+	if (chn->binary) {
+		memcpy(chn->data + structoff, &data, sizeof(data));
+		return 0;
+	}
+	return blkid_probe_sprintf_value(pr, name, "%lu", data);
+}
+
+
+/* the topology info is complete when we have at least "minimum_io_size" which
+ * is provided by all blkid topology drivers */
+static int topology_is_complete(blkid_probe pr)
+{
+	struct blkid_chain *chn = blkid_probe_get_chain(pr);
+
+	if (!chn)
+		return FALSE;
+
+	if (chn->binary && chn->data) {
+		blkid_topology tp = (blkid_topology) chn->data;
+		if (tp->minimum_io_size)
+			return TRUE;
+	}
+
+	return __blkid_probe_lookup_value(pr, "MINIMUM_IO_SIZE") ? TRUE : FALSE;
+}
+
+int blkid_topology_set_alignment_offset(blkid_probe pr, int val)
+{
+	unsigned long xval;
+
+	/* Welcome to Hell. The kernel is able to return -1 as an
+	 * alignment_offset if no compatible sizes and alignments
+	 * exist for stacked devices.
+	 *
+	 * There is no way how libblkid caller can respond to the value -1, so
+	 * we will hide this corner case...
+	 *
+	 * (TODO: maybe we can export an extra boolean value 'misaligned' rather
+	 *  then complete hide this problem.)
+	 */
+	xval = val < 0 ? 0 : val;
+
+	return topology_set_value(pr,
+			"ALIGNMENT_OFFSET",
+			offsetof(struct blkid_struct_topology, alignment_offset),
+			xval);
+}
+
+int blkid_topology_set_minimum_io_size(blkid_probe pr, unsigned long val)
+{
+	return topology_set_value(pr,
+			"MINIMUM_IO_SIZE",
+			offsetof(struct blkid_struct_topology, minimum_io_size),
+			val);
+}
+
+int blkid_topology_set_optimal_io_size(blkid_probe pr, unsigned long val)
+{
+	return topology_set_value(pr,
+			"OPTIMAL_IO_SIZE",
+			offsetof(struct blkid_struct_topology, optimal_io_size),
+			val);
+}
+
+/* BLKSSZGET is provided on all systems since 2.3.3 -- so we don't have to
+ * waste time with sysfs.
+ */
+static int topology_set_logical_sector_size(blkid_probe pr)
+{
+	unsigned long val = blkid_probe_get_sectorsize(pr);
+
+	if (!val)
+		return -1;
+
+	return topology_set_value(pr,
+			"LOGICAL_SECTOR_SIZE",
+			offsetof(struct blkid_struct_topology, logical_sector_size),
+			val);
+}
+
+int blkid_topology_set_physical_sector_size(blkid_probe pr, unsigned long val)
+{
+	return topology_set_value(pr,
+			"PHYSICAL_SECTOR_SIZE",
+			offsetof(struct blkid_struct_topology, physical_sector_size),
+			val);
+}
+
+/**
+ * blkid_topology_get_alignment_offset:
+ * @tp: topology
+ *
+ * Returns: alignment offset in bytes or 0.
+ */
+unsigned long blkid_topology_get_alignment_offset(blkid_topology tp)
+{
+	return tp->alignment_offset;
+}
+
+/**
+ * blkid_topology_get_minimum_io_size:
+ * @tp: topology
+ *
+ * Returns: minimum io size in bytes or 0.
+ */
+unsigned long blkid_topology_get_minimum_io_size(blkid_topology tp)
+{
+	return tp->minimum_io_size;
+}
+
+/**
+ * blkid_topology_get_optimal_io_size
+ * @tp: topology
+ *
+ * Returns: optimal io size in bytes or 0.
+ */
+unsigned long blkid_topology_get_optimal_io_size(blkid_topology tp)
+{
+	return tp->optimal_io_size;
+}
+
+/**
+ * blkid_topology_get_logical_sector_size
+ * @tp: topology
+ *
+ * Returns: logical sector size (BLKSSZGET ioctl) in bytes or 0.
+ */
+unsigned long blkid_topology_get_logical_sector_size(blkid_topology tp)
+{
+	return tp->logical_sector_size;
+}
+
+/**
+ * blkid_topology_get_physical_sector_size
+ * @tp: topology
+ *
+ * Returns: logical sector size (BLKSSZGET ioctl) in bytes or 0.
+ */
+unsigned long blkid_topology_get_physical_sector_size(blkid_topology tp)
+{
+	return tp->physical_sector_size;
+}
+